There is a voice recognition system in which an inputted voice is transmitted from a terminal to a server and recognized by the server.
For instance, in a vehicle, as a voice of “route search (ráut s{acute over (∂)} t∫)” uttered by a crew is inputted into an in-vehicle terminal, the in-vehicle terminal transmits the inputted voice to a voice recognition server through a phone network. As the voice recognition server receives the voice, it retrieves and computes a route from a current position of a vehicle to a destination. It then transmits a result of retrieving the route to the in-vehicle terminal through the phone network. As the in-vehicle terminal receives the result, it then displays the result. The crew who uttered “route search” is thereby enabled to recognize the route from the current position to the destination.
Here, the inputted voice is transmitted from the in-vehicle terminal to the voice recognition server through wireless communication. If radio wave environment relating to the wireless communication is deteriorated, quality of the transmitted voice may be lowered (e.g, due to accumulated noise component). This involves high probability of mis-recongnition in the voice recognition server or poor performance of the voice recognition.
In the vehicle, there are noisy conditions such as a blasting of an air-conditioner, an output of an audio, or operational noise of wipers. According to a state of the vehicle, the above noises become relatively louder than the inputted voice, so that the quality of the transmitted voice is lowered. Furthermore, operation of some in-vehicle devices may adversely affect wireless communication by acting as a signal noise. This also causes the high probability of mis-recognition in the voice recognition server or the poor performance of the voice recognition.